For they speak not peace - They seek a quarrel. They are unwilling to be on good terms with others, or to live in peace with them. The idea is that they were “disposed” or “inclined” to quarrel. Thus we speak now of persons who are “quarrelsome.
They devise deceitful matters - literally, “they think of words of deceit.” That is, they set their hearts on misrepresentation, and they study such misrepresentations as occasions for strife with others. They falsely represent my character; they attribute conduct to me of which I am not guilty; they pervert my words; they state that to be true which never occurred, and thus they attempt to justify their own conduct. Almost all the quarrels in the world, whether pertaining to nations, to neighborhoods, to families, or to individuals, are based on some “misrepresentation” of facts, designed or undesigned, and could have been avoided if men had been willing to look at facts as they are, or perfectly understood each other.
Against them that are quiet in the land - That are disposed to be quiet, or that are inclined to live in peace with those around them. The word rendered “quiet” means literally those who are “timid;” then, those who shrink back, and gather together from fear; then, those in general who are disposed to be peaceful and quiet, or who are indisposed to contention and strife. David implicitly asserts himself to be one of that class; a man who preferred peace to war, and who had no disposition to keep up a strife with his neighbors.